Here is a neat solution if you need to capture several different video sources at the same time. This USB device lets you hook up to 4 different video channels and features recording of up to 25 fps under PAL format and 30 fps under NTSC format. The software use MPEG4 video as video decoder and the quality can be set in 5 different levels and you can even choose frame rate from 1 to 30 fps for each channel. The price is $38. More photos and a screenshot of the software inside.

USB EasyCap 4 Channel DVR [brando.com.hk]